From cc87d1502c1151ab6a4ebcac31a38a8adfd72d02 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Sat, 28 May 2022 17:45:34 -0500
Subject: [PATCH] MSM6295: add rate select effect (20xx)

---
 src/engine/platform/msm6295.cpp | 51 +++++++++++++++++++++++++++------
 src/engine/platform/msm6295.h   |  1 +
 src/engine/sysDef.cpp           | 13 ++++++++-
 3 files changed, 55 insertions(+), 10 deletions(-)

diff --git a/src/engine/platform/msm6295.cpp b/src/engine/platform/msm6295.cpp
index c426af014..b2c725cb0 100644
--- a/src/engine/platform/msm6295.cpp
+++ b/src/engine/platform/msm6295.cpp
@@ -23,13 +23,18 @@
 #include <string.h>
 #include <math.h>
 
-#define rWrite(v) if (!skipRegisterWrites) {writes.emplace(0,v); if (dumpWrites) {addWrite(0,v);} }
+#define rWrite(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
 
 const char** DivPlatformMSM6295::getRegisterSheet() {
   return NULL;
 }
 
 const char* DivPlatformMSM6295::getEffectName(unsigned char effect) {
+  switch (effect) {
+    case 0x20:
+      return "20xx: Set chip output rate (0: clock/132; 1: clock/165)";
+      break; 
+  }
   return NULL;
 }
 
@@ -42,6 +47,27 @@ void DivPlatformMSM6295::acquire(short* bufL, short* bufR, size_t start, size_t
     if (delay<=0) {
       if (!writes.empty()) {
         QueuedWrite& w=writes.front();
+        switch (w.addr) {
+          case 0: // command
+            break;
+          case 8: // chip clock select (VGM)
+          case 9:
+          case 10:
+          case 11:
+            break;
+          case 12: // rate select
+            msm->ss_w(w.val);
+            break;
+          case 14: // enable bankswitch
+            break;
+          case 15: // set bank base
+            break;
+          case 16: // switch bank
+          case 17:
+          case 18:
+          case 19:
+            break;
+        }
         msm->command_w(w.val);
         writes.pop();
         delay=32;
@@ -92,9 +118,9 @@ int DivPlatformMSM6295::dispatch(DivCommand c) {
           }
           chan[c.chan].active=true;
           chan[c.chan].keyOn=true;
-          rWrite((8<<c.chan)); // turn off
-          rWrite(0x80|chan[c.chan].sample); // set phrase
-          rWrite((16<<c.chan)|(8-chan[c.chan].outVol)); // turn on
+          rWrite(0,(8<<c.chan)); // turn off
+          rWrite(0,0x80|chan[c.chan].sample); // set phrase
+          rWrite(0,(16<<c.chan)|(8-chan[c.chan].outVol)); // turn on
         } else {
           break;
         }
@@ -107,9 +133,9 @@ int DivPlatformMSM6295::dispatch(DivCommand c) {
         }
         //DivSample* s=parent->getSample(12*sampleBank+c.value%12);
         chan[c.chan].sample=12*sampleBank+c.value%12;
-        rWrite((8<<c.chan)); // turn off
-        rWrite(0x80|chan[c.chan].sample); // set phrase
-        rWrite((16<<c.chan)|(8-chan[c.chan].outVol)); // turn on
+        rWrite(0,(8<<c.chan)); // turn off
+        rWrite(0,0x80|chan[c.chan].sample); // set phrase
+        rWrite(0,(16<<c.chan)|(8-chan[c.chan].outVol)); // turn on
       }
       break;
     }
@@ -117,14 +143,14 @@ int DivPlatformMSM6295::dispatch(DivCommand c) {
       chan[c.chan].keyOff=true;
       chan[c.chan].keyOn=false;
       chan[c.chan].active=false;
-      rWrite((8<<c.chan)); // turn off
+      rWrite(0,(8<<c.chan)); // turn off
       chan[c.chan].macroInit(NULL);
       break;
     case DIV_CMD_NOTE_OFF_ENV:
       chan[c.chan].keyOff=true;
       chan[c.chan].keyOn=false;
       chan[c.chan].active=false;
-      rWrite((8<<c.chan)); // turn off
+      rWrite(0,(8<<c.chan)); // turn off
       chan[c.chan].std.release();
       break;
     case DIV_CMD_ENV_RELEASE:
@@ -153,6 +179,10 @@ int DivPlatformMSM6295::dispatch(DivCommand c) {
     case DIV_CMD_NOTE_PORTA: {
       return 2;
     }
+    case DIV_CMD_SAMPLE_FREQ:
+      rateSel=c.value;
+      rWrite(12,rateSel);
+      break;
     case DIV_CMD_SAMPLE_BANK:
       sampleBank=c.value;
       if (sampleBank>(parent->song.sample.size()/12)) {
@@ -190,6 +220,7 @@ void DivPlatformMSM6295::forceIns() {
   for (int i=0; i<4; i++) {
     chan[i].insChanged=true;
   }
+  rWrite(12,rateSel);
 }
 
 void* DivPlatformMSM6295::getChanState(int ch) {
@@ -219,6 +250,7 @@ void DivPlatformMSM6295::poke(std::vector<DivRegWrite>& wlist) {
 void DivPlatformMSM6295::reset() {
   while (!writes.empty()) writes.pop();
   msm->reset();
+  msm->ss_w(false);
   if (dumpWrites) {
     addWrite(0xffffffff,0);
   }
@@ -232,6 +264,7 @@ void DivPlatformMSM6295::reset() {
   }
 
   sampleBank=0;
+  rateSel=false;
 
   delay=0;
 }
diff --git a/src/engine/platform/msm6295.h b/src/engine/platform/msm6295.h
index bedaab41c..d63a01dc7 100644
--- a/src/engine/platform/msm6295.h
+++ b/src/engine/platform/msm6295.h
@@ -101,6 +101,7 @@ class DivPlatformMSM6295: public DivDispatch {
     int delay, updateOsc;
 
     bool extMode;
+    bool rateSel;
   
     short oldWrites[512];
     short pendingWrites[512];
diff --git a/src/engine/sysDef.cpp b/src/engine/sysDef.cpp
index cb3d5e2f2..2ef13df2f 100644
--- a/src/engine/sysDef.cpp
+++ b/src/engine/sysDef.cpp
@@ -1954,7 +1954,18 @@ void DivEngine::registerSystems() {
     {"Channel 1", "Channel 2", "Channel 3", "Channel 4"},
     {"CH1", "CH2", "CH3", "CH4"},
     {DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM, DIV_CH_PCM},
-    {DIV_INS_AMIGA, DIV_INS_AMIGA, DIV_INS_AMIGA, DIV_INS_AMIGA}
+    {DIV_INS_AMIGA, DIV_INS_AMIGA, DIV_INS_AMIGA, DIV_INS_AMIGA},
+    {},
+    [this](int ch, unsigned char effect, unsigned char effectVal) -> bool {
+      switch (effect) {
+        case 0x20: // select rate
+          dispatchCmd(DivCommand(DIV_CMD_SAMPLE_FREQ,ch,effectVal));
+          break;
+        default:
+          return false;
+      }
+      return true;
+    }
   );
 
   sysDefs[DIV_SYSTEM_MSM6258]=new DivSysDef(